I was looking to see the labellum on this Bunochilus, but it had been triggered. I could see some legs poking out, and as I watched, this fungus gnat finally crawled free of the labellem and galea. Once free, it was persistently trying to get back at the labellum which was still triggered. I watched it for around 45 minutes, but the labellum didn't reset in this time.
Have been checking greenhoods and helmets for fungus gnats with colleagues for the past year and this is one of the best pictures to emerge of sexual deceit of the males. Tobias has a movie of the process on YouTube.